Organic compound and organic light emitting diode using the same

ABSTRACT

Discussed is an organic electroluminescent device including a first charge carrying layer being disposed adjacent to a first electrode; and a second charge carrying layer disposed adjacent to a second electrode, wherein the first charge carrying layer includes an emitting part, a hole injection part and a hole transporting part between the hole injection part and the emitting part, wherein at least one of the hole injection part, the hole transporting part and the emitting part includes a host material having an organic compound of Formula: 
                         
wherein R is substituted or non-substituted C1 to C12 alkyl, and A and B are symmetrically or asymmetrically positioned in 2-position or 7-position of the fluorene core, and wherein each of A and B is independently selected from substituted or non-substituted aromatic group or substituted or non-substituted heterocyclic group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Korean PatentApplication Nos. 10-2013-0150833 and 10-2014-0089253, filed in Korea onDec. 5, 2013 and Jul. 15, 2014, respectively, all of which are herebyincorporated by reference in their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The embodiments of the invention relate to an organic light emittingdiode (OLED) and more particularly to an organic compound being capableof reducing a driving voltage and being adequate to a simple structureOLED and an OLED including the organic compound.

2. Discussion of the Related Art

Developments in information have led to developments in flat paneldisplay devices as an image displaying device. The flat panel displaydevice includes a liquid crystal display (LCD), a plasma display panel(PDP), a field emission display (FED) and an organic light emittingdiode device (OLED), and the flat panel display device meeting thedemand for thinness, light-weight and low power consumption areintroduced.

Among the flat panel display devices, the OLED has various advantages ascompared to the LCD, the PDP and the FED. A flexible substrate, forexample, a plastic substrate, can be used as a base substrate for theOLED, and the OLED has excellent characteristics of driving voltage andpower consumption.

FIG. 1 is a cross-sectional view of a related art OLED.

As shown in FIG. 1, the OLED 20 is formed on a substrate 10 and includesa first electrode 21 as an anode, a second electrode 27 as a cathode,and an organic emitting layer therebetween. To increase an emissionefficiency, the organic emitting layer includes a hole injection layer(HIL) 22, a hole transporting layer (HTL) 23, an emitting material layer(EML) 24 and an electron transporting layer (ETL) 25 and an electroninjection layer (EIL) 26.

Holes are provided from the first electrode 21 into the EML 24 throughthe HIL 22 and the HTL 23, and electrons are provided from the secondelectrode 27 into the EML 24 through the EIL 26 and the ETL 25.

The holes and the electrons are combined to form excitons, and theexcitons are transformed from an excited state to a ground state. As aresult, the OLED 20 emits light.

As mentioned above, the OLED requires a plurality of layers to increasethe emission efficiency. To prevent the quenching problem of theexcitons, the OLED further requires an electron blocking layer and ahole blocking layer. As a result, the production costs of the OLED areincreased, and the production yield of the OLED is decreased.

In addition, there are still barriers between adjacent layers.Particularly, there is a hole injection barrier between the HIL 22 andthe HTL 23 and/or between the HTL 23 and the ML 24, and the velocity ofthe electron injection and the electron transporting is larger than thatof the hole injection and the hole transporting. Accordingly, thecombination of the holes and the electrons is generated in a boundaryregion between the EML 24 and the HTL 23—not a center region of the EML24—such that the emission efficiency is decreased and the drivingvoltage is increased.

To resolve the above problems, the simple structure OLED is required. Inaddition, a balance of the velocity of the holes and the electrons isrequired to form the excitons in the center region of the EML.

SUMMARY OF THE INVENTION

Accordingly, the embodiment of the invention is directed to an organiccompound and an OLED using the same that substantially obviate one ormore of the problems due to limitations and disadvantages of the relatedart.

An object of the embodiment of the invention is to provide an organiccompound being capable of reducing a driving voltage.

An object of the embodiment of the invention is to provide an organiccompound being adequate to a simple structure OLED

Another object of the embodiment of the invention is to provide an OLEDhaving a simple structure and an improved emission efficiency.

Additional features and advantages of the invention will be set forth inthe description which follows, and in part will be apparent from thedescription, or may be learned by practice of the invention. Theobjectives and other advantages of the invention will be realized andattained by the structure particularly pointed out in the writtendescription and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purposeof the embodiments of the invention, as embodied and broadly describedherein, an aspect of an embodiment of the invention provides an organicelectroluminescent device including a first electrode; a secondelectrode facing the first electrode; a first charge carrying layerdisposed between the first electrode and the second electrode, the firstcharge carrying layer being disposed adjacent to the first electrode;and a second charge carrying layer disposed between the first electrodeand the second electrode, the second charge carrying layer disposedadjacent to the second electrode, wherein the first charge carryinglayer includes an emitting part, a hole injection part and a holetransporting part between the hole injection part and the emitting part,wherein at least one of the hole injection part, the hole transportingpart and the emitting part includes a host material having an organiccompound of Formula:

wherein R is substituted or non-substituted C1 to C12 alkyl, and A and Bare symmetrically or asymmetrically positioned in 2-position or7-position of the fluorene core, and wherein each of A and B isindependently selected from substituted or non-substituted aromaticgroup or substituted or non-substituted heterocyclic group.

In another aspect of the embodiment of the invention, provided is anorganic electroluminescent device including a first electrode; a secondelectrode facing the first electrode; a first charge carrying layerdisposed between the first electrode and the second electrode, the firstcharge carrying layer being disposed adjacent to the first electrode;and a second charge carrying layer disposed between the first electrodeand the second electrode, the second charge carrying layer disposedadjacent to the second electrode, wherein the first charge carryinglayer includes an emitting part, a hole injection part and a holetransporting part between the hole injection part and the emitting part,wherein at least one of the hole injection part, the hole transportingpart and the emitting part includes a host material having an organiccompound of Formula:

wherein X is selected from carbon, nitrogen, oxygen and sulfur, and Y isselected from aryl and arylamine.

In another aspect of the embodiment of the invention provided is anorganic electroluminescent device including a first electrode; a secondelectrode facing the first electrode; a first charge carrying layerdisposed between the first electrode and the second electrode, the firstcharge carrying layer being disposed adjacent to the first electrode;and a second charge carrying layer disposed between the first electrodeand the second electrode, the second charge carrying layer disposedadjacent to the second electrode, wherein the first charge carryinglayer includes an emitting part, a hole injection part and a holetransporting part between the hole injection part and the emitting part,and wherein at least two of the emitting part, the hole injection partand the hole transporting part include the same host material.

It is to be understood that both the foregoing general description andthe following detailed description are by example and explanatory andare intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

FIG. 1 is a cross-sectional view of the related art OLED.

FIG. 2 is a schematic cross-sectional view of an OLED according to afirst embodiment of the invention.

FIG. 3 is a schematic cross-sectional view of an OLED according to asecond embodiment of the invention.

FIG. 4 is a schematic cross-sectional view of an OLED according to athird embodiment of the invention.

FIG. 5 is a graph showing a current density according to a drivingvoltage in an OLED of an example 1 of the embodiment of the invention.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to example embodiments, examples ofwhich are illustrated in the accompanying drawings.

FIG. 2 is a schematic cross-sectional view of an OLED according to afirst embodiment of the invention.

As shown in FIG. 2, OLED 200 is formed on a substrate 100 and includes afirst electrode 210, a hole injection layer (HIL) 230, a holetransporting layer (HTL) 240, an emitting material layer (EML) 250 andan electron transporting layer (ETL) 260, an electron injection layer(EIL) 270 and a second electrode 280.

The first electrode 210 includes a conductive material having arelatively high work function. For example, the first electrode 210 mayinclude indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). However, thematerial is not limited thereto.

The HIL 230 is formed on the first electrode 210 as an anode, andincludes an organic compound in Formula 1. The organic compound inFormula 1 has a hole transporting property.

In Formula 1, R is substituted or non-substituted C1 to C12 alkyl. A andB are symmetrically or asymmetrically positioned in 2-position or7-position of the fluorene core, and each of A and B is independentlyselected from substituted or non-substituted aromatic group orsubstituted or non-substituted heterocyclic group.

For example, each of A and B is independently selected from substitutedor non-substituted carbazole, substituted or non-substitutedα-carboline, substituted or non-substituted β-carboline, substituted ornon-substituted γ-carboline, substituted or non-substituteddibenzofuran, substituted or non-substituted dibenzothiophene,substituted or non-substituted aryl amine, substituted ornon-substituted aryl silane and substituted or non-substituted phenyl.

Each of A and B is independently selected from the following compounds.

The organic compound in Formula 1 includes the following compounds FL-1to FL-26.

The HIL 230 further includes a dopant material 220 having a lowestunoccupied molecular orbital (LUMO) level of −4.5 eV to −6.0 eV. Forexample, the dopant material 220 may be an organic compound in Formula2, but it is not limited thereto. The dopant material 220 may have 0.1to 20 weight % with respect to a total weight of the HIL 230. Namely,the dopant material 220 is doped to the organic compound in Formula 1 toform the HIL 230 of the OLED 200.

Synthesis Example

A synthesis example of the organic compound is explained.

1. Synthesis of the Compound FL-1

2,7-dibromo-9,9-dimethyl-9H-fluorene (10 g, 28.403 mmol), carbazole (9.5g, 56.806 mmol), copper iodide (CuI) (4.3 g, 22.722 mmol), K₃PO₄ (36 g,170.418 mmol), and trans-1,2-cyclohexanediamine (2.7 mL, 22.722 mmol)were dissolved in 1,4-dioxane. The solution was refluxed and stirred for12 hours. After completion of the reaction, the solution was distilledunder reduced pressure to remove the solvent. The resultant was columnedwith a solvent of n-hexane and methylene chloride (4:1) and wasshort-columned with toluene. The solution was distilled under reducedpressure and was re-crystallized in a solution of methylene chloride andpetroleum ether such that the compound FL-1 was obtained, (4.0 g, yield:67%).

2. Synthesis of the Compound FL-2

2,7-dibromo-9,9-dimethyl-9H-fluorene (10 g, 28.403 mmol), carbazole(2.37 g, 14.20 mmol), copper iodide (Cup (540 mg, 2.840 mmol), K₃PO₄(6.03 g, 28.404 mmol), and trans-1,2-cyclohexanediamine (0.34 mL, 2.840mmol) were dissolved in 1,4-dioxane. The solution was refluxed andstirred for 12 hours. After completion of the reaction, the solution wasdistilled under reduced pressure to remove the solvent. The resultantwas columned with a solvent of n-hexane and methylene chloride (4:1).The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the compound X1 was obtained, (4.17 g, yield: 67%).

The compound X1 (2.0 g, 4.562 mmol), diphenylamine (701 mg, 4.148 mmol),tris-(t-butyl)-phosphine (49 μl, 0.207 mmol), and sodium tert-butoxide(798 mg, 8.296 mmol) were dissolved in toluene. The solution wasrefluxed and stirred for 12 hours with catalyst of palladium(II)acetate(Pd(OAc)₂). After completion of the reaction, the solution was distilledunder reduced pressure to remove the solvent. The resultant was columnedwith a solvent of n-hexane and methylene chloride (3:1). The solutionwas distilled under reduced pressure and was re-crystallized in asolution of methylene chloride and petroleum ether such that thecompound FL-2 was obtained, (1.5 g, yield: 69%).

3. Synthesis of the Compound FL-3

1,3-dibromobenzene (24.9 mL, 206.83 mmol), diphenylamine (10 g, 59.095mmol), tri-ortho-tolyphosphine (899 mg, 2.955 mmol) and sodiumtert-butoxide (11.4 g, 118.19 mmol) were dissolved in toluene. Thesolution was refluxed and stirred for 12 hours with catalyst oftris(dibenzylideneacetone)dipalladium(0) (Pd₂(dba)₃). After completionof the reaction, the solution was distilled under reduced pressure toremove the solvent. The resultant was columned with n-hexane. Thesolution was distilled under reduced pressure and was re-crystallized ina solution of methylene chloride and petroleum ether such that thecompound X2 was obtained, (9.26 g, yield: 48%).

The compound X2 (8.9 g, 27.451 mmol) was dissolved in tetrahydrofuran(THF). The solution was cooled into −78° C., and 2.5M n-butyl lithium(n-BuLi) solution (14.3 mL) was slowly dropped. The solution was stirredin a room temperature for 1 hour. The solution was cooled again into−78° C., and triethyl borate (7.0 mL, 41.176 mmol) was slowly dropped.The solution was stirred in a room temperature for 12 hours. After 12hours, 5N HCl solution (50 mL) was added, and THF was removed. Theresultant was extracted by distilled water and methylene chloride. Theresultant was distilled under reduced pressure to remove the solvent andwas columned with methylene chloride. The solution was distilled underreduced pressure such that the compound X-3 was obtained, (4.73 g,yield: 60%).

The compound X1 (2.06 g, 4.7 mmol), the compound X3 (1.63 g, 5.64 mmol),potassium carbonate (K₂CO₃) (1.30 mg, 9.4 nnol) were dissolved intoluene and distilled water. The solution was refluxed and stirred for12 hours with catalyst of tetrakis(triphenylphosphine)palladium(0) (217mg, 0.19 mmol). After completion of the reaction, the solution wasdistilled under reduced pressure to remove the solvent. The resultantwas columned with a solvent of n-hexane and methylene chloride (4:1).The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the compound FL-3 was obtained, (0.74 g, yield: 26%).

4. Synthesis of the Compound FL-4

2,7-dibromo-9,9-dimethyl-9H-fluorene (5.0 g, 14.2 mmol), copper iodide(CuI) (649 mg, 3.41 mmol), sodium iodide (NaI) (8.5 g, 56.804 mmol), andtrans-1,2-diaminomethylamine (0.99 mL, 6.25 mmol) were dissolved in1,4-dioxane. The solution was refluxed and stirred for 12 hours. Aftercompletion of the reaction, the solution was distilled under reducedpressure to remove the solvent. The resultant was columned withn-hexane. The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the compound X4 was obtained, (4.17 g, yield: 65%).

The compound X4 (2.5 g, 5.59 mmol), carboline (2.07 g, 12.307 mmol),copper iodide (CuI) (852 mg, 4.48 mmol), K₃PO₄ (7.13 g, 33.57 mmol), andtrans-1,2-cyclohexanediamine (0.54 mL, 4.48 mmol) were dissolved in1,4-dioxane. The solution was refluxed and stirred for 12 hours. Aftercompletion of the reaction, the solution was distilled under reducedpressure to remove the solvent. The resultant was columned with asolvent of n-hexane and ethylacetate (3:1). The solution was distilledunder reduced pressure and was re-crystallized in a solution ofmethylene chloride and petroleum ether such that the compound FL-4 wasobtained, (1.08 g, yield: 37%).

5. Synthesis of the Compound FL-11 (1) Synthesis of2-(7-bromo-9,9-dimethyl-9H-fluoren-2-yl)dibenzo[b,d]thiophene

2,7-dibromo-9,9-dimethyl-9H-fluorene (5.0 g, 14.201 mmol),dibenzo[b,d]thiophen-2-ylboronic acid (1.62 g, 7.10 mmol), Pd(pph₃)₄(820 mg, 0.71 mmol), K₂CO₃ (1.96 g, 14.201 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene/H₂O. The solution was refluxedand stirred for 12 hours. After completion of the reaction, the solutionwas distilled under reduced pressure to remove the solvent. Theresultant was columned with a solution of hexane and methylenechloride(9:1). The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the white solid compound was obtained, (1.61 g, yield: 50%).

(2) Synthesis of the Compound FL-11

2-(7-bromo-9,9-dimethyl-9H-fluoren-2-yl)dibenzo[b,d]thiophene (1.61 g,3.54 mmol), 3-(diphenylamino)phenylboronic acid (1.02 g, 3.54 mmol),Pd(pph3)4 (404 mg, 0.35 mmol), K₂CO₃ (978 mg, 7.08 mmol) were put in a250 mL two-neck flask and dissolved in toluene/H₂O. The solution wasrefluxed and stirred for 12 hours. After completion of the reaction, thesolution was distilled under reduced pressure to remove the solvent. Theresultant was columned with a solution of hexane and methylenechloride(4:1). The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the compound FL-11 of white solid was obtained, (1.50 g,yield: 68%).

6. Synthesis of the Compound FL-12 (1) Synthesis of2-(7-bromo-9,9-dimethyl-9H-fluoren-2-yl)dibenzo[b,d]furan

2,7-dibromo-9,9-dimethyl-9H-fluorene (5.0 g, 14.201 mmol),dibenzo[b,d]furan-2-ylboronic acid (1.50 g, 7.10 mmol), Pd(pph3)4 (820mg, 0.71 mmol), K₂CO₃ (1.96 g, 14.201 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene/H₂O. The solution was refluxedand stirred for 12 hours. After completion of the reaction, the solutionwas distilled under reduced pressure to remove the solvent. Theresultant was columned with a solution of hexane and methylenechloride(8:1). The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the white solid compound was obtained, (1.50 g, yield: 48%).

(2) Synthesis of the Compound FL-12

2-(7-bromo-9,9-dimethyl-9H-fluoren-2-yl)dibenzo[b,d]furan (1.50 g, 3.42mmol), 3-(diphenylamino)phenylboronic acid (989 mg, 3.42 mmol),Pd(pph3)4 (393 mg, 0.34 mmol), K₂CO₃ (945 mg, 6.84 mmol) were put in a250 mL two-neck flask and dissolved in toluene/H₂O. The solution wasrefluxed and stirred for 12 hours. After completion of the reaction, thesolution was distilled under reduced pressure to remove the solvent. Theresultant was columned with a solution of hexane and methylenechloride(3:1). The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the compound FL-12 of white solid was obtained, (1.20 g,yield: 58%).

7. Synthesis of the Compound FL-15 (1) Synthesis of3-(7-bromo-9,9-dimethyl-9H-fluoren-2-yl)-N,N-diphenylaniline

2,7-dibromo-9,9-dimethyl-9H-fluorene (5.0 g, 14.201 mmol),3-(diphenylamino)phenylboronic acid (2.05 g, 7.10 mmol), Pd(pph3)4 (820mg, 0.71 mmol), K₂CO₃ (1.96 g, 14.201 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene/H₂O. The solution was refluxedand stirred for 12 hours. After completion of the reaction, the solutionwas distilled under reduced pressure to remove the solvent. Theresultant was columned with a solution of hexane and methylenechloride(4:1). The solution was distilled under reduced pressure and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the white solid compound was obtained, (1.50 g, yield: 41%).

(2) Synthesis of the Compound FL-15

3-(7-bromo-9,9-dimethyl-9H-fluoren-2-yl)-N,N-diphenylaniline (1.50 g,2.90 mmol) were put in a 250 mL two-neck flask and dissolved indiethylether. The solution was cooled into −78° C., and n-BuLi (2.5M,1.74 mL) were dropped. After three hours, chlorotriphenylsilane (989 mg,3.42 mmol) dissolved in diethylether was slowly dropped, and thesolution was refluxed and stirred at a room temperature for 12 hours.After completion of the reaction, the solution was distilled underreduced pressure to remove the solvent. The resultant was columned witha solution of hexane and methylenechloride (5:1). The solution wasdistilled under reduced pressure and was re-crystallized in a solutionof methylene chloride and petroleum ether such that the compound FL-15of white solid was obtained, (1.20 g, yield: 59%).

The properties of the compounds FL-1 to FL-4, FL11, FL-12 and FL-15 andNPB(N,N′-di(naphthalen-1-yl)-N,N′-diphenyl-benzidine) were tested andlisted in Table 1.

TABLE 1 λ_(PL) ^(b) (nm) Band gap Compounds λ_(abs) ^(a) (nm) sol./77KEnergy ^(c) LUMO ^(d)(eV) HOMO ^(e) (eV) E_(T) (eV) NPB (ref.) 414 5403.00 −2.40 −5.40 2.30 FL-1 360 459 3.45 −2.13 −5.58 2.71 FL-2 390 4893.18 −2.43 −5.61 2.54 FL-3 374 491 3.32 −2.33 −5.65 2.53 FL-4 354 4583.51 −2.06 −5.57 2.71 FL-11 371 491 3.34 −2.32 −5.66 2.53 FL-12 370 4873.35 −2.33 −5.68 2.55 FL-15 372 485 3.34 −2.35 −5.69 2.56 ^(a)Absorptiononset of 0.02 mM solutions in CH₂Cl₂. ^(b)PL maxima of 2-methyl THFsolutions upon excitation at UV maximum absorption. ^(c) Estimated fromthe absorption onset. ^(d) LUMO = −[Band gap energy − HOMO level] ^(e)Estimated from the Cyclic Voltammetry instrument.

As shown in Table 1, a band gap energy of the compounds FL-1 to FL-4,FL11, FL-12 and FL-15 of the embodiment of the invention is larger thanthe band gap energy 3.0 of NPB. Accordingly, the organic compound of theembodiment of the invention can be used as a host material of the EML aswell as the material of HIL and HTL.

The HTL 240 is formed on the HIL 230. For example, the HTL 240 mayinclude NPB(N,N′-di(naphthalen-1-yl)-N,N′-diphenyl-benzidine), orPD(N,N′-bis-(3-methylphenyl)-N,N′-bis-(phenyl)-benzidine), but it is notlimited thereto.

The EML 250 is formed on the HTL 240 and may include a host materialwith a dopant material, which may be similar or the same as the dopantmaterial 220. Each of the host material and the dopant material isselected from a fluorescent compound and a phosphorescent compound, butit is not limited thereto. For example, for the blue EML 250, the hostmaterial may be a fluorescent compound of one of anthracene derivatives,pyrene derivatives and perylene derivatives, and the blue fluorescentdopant may be doped to the host compound. For the green EML 250, thehost material may be a phosphorescent compound of one of carbazolederivatives or a metal complex, and the green phosphorescent dopant maybe doped to the host compound. For the red EML 250, the host materialmay be a phosphorescent compound of one of carbazole derivatives or ametal complex, and the red phosphorescent dopant may be doped to thehost compound.

The ETL 260 is formed on the EML 250. The ETL 260 includes oxadiazole,triazole, phenanthroline, benzoxazole or benzthiazole, but it is notlimited thereto.

The EIL 270 is formed on the ETL 260. The EIL 270 includes LiF orlithium quinolate (LiQ), but it is not limited thereto.

The second electrode 280 is formed on the EIL 270 and includes ametallic material having a relatively low work function. For example,the second electrode 280 may include aluminum (Al), silver (Ag),magnesium (Mg), lithium (Li) or calcium (Ca), but it is not limitedthereto.

FIG. 3 is a schematic cross-sectional view of an OLED according to asecond embodiment of the invention. The OLED in FIG. 3 is substantiallysame as that in FIG. 2 except the material of the HTL. Accordingly, theexplanation is focused on the material of the HTL.

As shown in FIG. 3, each of the HIL 230 and the HTL 240′ of the OLED 200of the embodiment of the invention includes the organic compound inFormula 1. As explained above, the HIL 230 further includes the dopantmaterial 220 having the LUMO level of −4.5 eV to −6.0 eV. For example,the dopant material 220 may be an organic compound in Formula 2.

In the OLED 200, there is no hole injection barrier between the HIL 230and the HTL 240′ (indicated by a dashed line), and the driving voltageof the OLED is lowered. In addition, since the HIL 230 and the HTL 240′include the same material, the production costs is decreased and theproduction yield is improved. The dopant material 220 may have 0.1 to 20weight % with respect to a total weight of the HIL 230.

FIG. 4 is a schematic cross-sectional view of an OLED according to athird embodiment of the invention. The OLED in FIG. 4 is substantiallysame as that in FIG. 2 except the material of the HTL and the EML.Accordingly, the explanation is focused on the material of the HTL andEML.

As shown in FIG. 4, not only the HIL 230 and the HTL 240′ but also theEML 250′ of the OLED 200 of the embodiment of the invention includes theorganic compound in Formula 1. As explained above, the HIL 230 furtherincludes the dopant material 220 having the LUMO level of −4.5 eV to−6.0 eV. For example, the dopant material 220 may be an organic compoundin Formula 2. The dopant material 220 may have 0.1 to 20 weight % withrespect to a total weight of the HIL 230.

In addition, the EML 250′ may further include the dopant material to theorganic compound in Formula 1 as a host material. The dopant materialfor the EML 250′ may be a fluorescent compound or a phosphorescentcompound.

In the OLED 200, there is no hole injection barrier between the HIL 230and the HTL 240′ and between the HTL 240′ and the EML 250′ (indicated bydashed lines), and the driving voltage of the OLED is lowered. Inaddition, since the HIL 230, the HTL 240′ and the EML 250′ include thesame material, the production costs is decreased and the productionyield is improved. The HIL 230, the HTL 240′, and the EML 250′ may bereferred to as a hole injection part, a hole transport part, and anemitting part in embodiments of the invention, for example, when no holeinjection barrier is present therebetween based on one or more of theparts containing a same host material. Also, in embodiments of theinvention, the hole injection part, the hole transport part, and theemitting part may be referred together as a first charge carrying layer201. That is, the first charge carrying layer may include hole injectionpart, the hole transport part, and the emitting part. Also, inembodiments of the invention, the ETL 260 and the EIL 270 may bereferred together as a second charge carrying layer 202. That is, thesecond charge carrying layer may include the ETL 260 and the EIL 270.

Example 1 1. Example Diode 1

An indium-tin-oxide (ITO) layer is patterned on a substrate and washedsuch that an emission area of the ITO layer is to be 3 mm*3 mm. Thesubstrate is washed by the UV ozone and is loaded in an evaporationsystem. The substrate is loaded in a vacuum chamber, and the processpressure is adjusted to 1*10⁻⁶˜1*10⁻⁷ torr. The compound FL-1 as a hostmaterial is deposited with HAT-CN in Formula 2 (10%) as a dopantmaterial to form the HIL (50 Å). NPB is deposited on the HIL to form theHTL (600 Å). MADN (2-methyl-9,10-bis(naphthalene-2-yl)anthracene) isdeposited on the HTL to form the EML (250 Å). NPB is deposited on theEML to form the hole blocking layer (100 Å). Aluminum is deposited onthe hole blocking layer to form the cathode (1500 Å). The UV curableepoxy and the getter are used for encapsulation such that the diode isobtained.

2. Example Diode 2

The compound FL-2 is used instead of the compound FL-1.

3. Comparative Example Diode 1

The HIL is formed by depositing HAT-CN without the host material in theHIL of the Example diode 1.

4. Comparative Example Diode 2

NPB is used instead of the host material in the HIL of the Example diode1.

The current and voltage property in the Example diodes 1 and 2 and theComparative Example diodes 1 and 2 were tested and shown in FIG. 5.

As shown in FIG. 5, in comparison to the Comparative Example diode 1,where only HAT-CN is used for the HIL, the driving voltage of theComparative Example diode 2, where NPB with HAT-CN is used for the HIL,is lowered. At 10 mA/cm2, the Comparative Example diode 1 has thedriving voltage of 8.5V, and the Comparative Example diode 2 has thedriving voltage of 7.7V.

In addition, in comparison to the Comparative Example diodes 1 and 2,the driving voltage of the Example diodes 1 and 2, where each of thecompounds FL-1 and FL-2 with HAT-CN is used for the HIL, is lowered. At10 mA/cm2, the Example diode 1 has the driving voltage of 7.3V, and theExample diode 2 has the driving voltage of 6.3V.

Example 2 1. Example Diode 3

An indium-tin-oxide (ITO) layer is patterned on a substrate and washedsuch that an emission area of the ITO layer is to be 3 mm*3 mm. Thesubstrate is washed by the UV ozone and is loaded in an evaporationsystem. The substrate is loaded in a vacuum chamber, and the processpressure is adjusted to 1*10⁻⁶˜1*10⁻⁷ torr. The compound FL-1 as a hostmaterial is deposited with HAT-CN in Formula 2 (10%) as a dopantmaterial to form the HIL (50 Å). Only the compound FL-1 is deposited onthe HIL to form the HTL (300 Å). The compound FL-1 as a host materialwith 4,48-bis(2,28-diphenylvinyl)-1,18-biphenyl (DPVBi) (15%) as adopant material is deposited on the HTL to form the EML (400 Å). Alq₃ isdeposited on the EML to form ETL (200 Å), and LiF is deposited on theETL to form the EIL (10 Å). Aluminum is deposited on the EIL to form thecathode (1000 Å). The UV curable epoxy and the getter are used forencapsulation such that the diode is obtained.

2. Example Diode 4

The compound FL-2 is used instead of the compound FL-1 in the Examplediode 3.

3. Example Diode 5

The compound FL-11 is used instead of the compound FL-1 in the Examplediode 3.

4. Example Diode 6

The compound FL-12 is used instead of the compound FL-1 in the Examplediode 3.

5. Example Diode 7

The compound FL-15 is used instead of the compound FL-1 in the Examplediode 3.

6. Comparative Example Diode

NPB is used instead of the compound FL-1 in the Example diode 3.

The properties of the Example diodes 3 to 7 and the Comparative Examplediode were tested and listed in Table 2.

TABLE 2 Emission Quantum Voltage efficiency efficiency [V] Cd/A Lm/W [%]CIEx CIEy Com. Ex. 3.19 1.01 0.99 1.17 0.144 0.098 Ex.1 3.20 3.30 3.243.70 0.142 0.110 Ex.2 3.07 3.50 3.58 4.06 0.141 0.108 Ex.3 3.10 1.731.75 2.02 0.143 0.098 Ex.4 3.10 1.72 1.74 2.00 0.144 0.098 Ex.5 3.101.33 1.35 1.57 0.142 0.098

Referring to Table 2, in comparison to the Comparative Example diode,the properties of the Example diodes 3 to 7 (listed as Ex. 1 to 5,respectively in Table 2) using the organic compound of the embodiment ofthe invention are improved. Particularly, the emission efficiency andthe quantum efficiency of the Example diode 4 (listed as Ex. 2) areremarkably improved, and the driving voltage of the Example diode 4(listed as Ex. 2) is remarkably lowered.

In the embodiment of the invention, the organic compound, which haslarge band gap energy and an excellent hole transporting property, isused for the host material of the HIL and EML and the material of theHTL such that the OLED has a simple structure and problems in theproduction costs and the production yield are overcome. In addition, thedopant material, which has a deep LUMO level, is used for the HIL suchthat the emission efficiency is improved and the driving voltage isreduced.

The HIL 230 in FIG. 2, the HIL 230 and the HTL 240′ in FIG. 3 and theHIL 230, the HTL 240′ and the EML 250′ in FIG. 4 include an organiccompound in Formula 3 instead of the organic compound in Formula 1. TheHIL 230 may further include a dopant material having a lowest unoccupiedmolecular orbital (LUMO) level of −4.5 eV to −6.0 eV. For example, thedopant material may be HAT-CN, which has 0.1 to 20 weight % with respectto a total weight of the HIL 230. The EML 250′ may further include ablue dopant material having 0.1 to 30 weight % with respect to a totalweight of the EML 250′ to emit blue light. For example, the dopantmaterial for the EML 250′ may beN,N′-bis(2,4-diphenyl)-N,N′-bis(2-fluorophenyl)-pyrene-1,6-diamine.

Namely, in the OLED including the first electrode, the HIL, the HTL, theEML and the second electrode, at least one of the HIL, the HTL and theEML includes the organic compound in Formula 3 such that the OLED hasadvantages in the emission efficiency, the quantum efficiency and thedriving voltage. Particularly, all of the HIL, the HTL and the EMLinclude the organic compound in Formula 3 such that the structure of theOLED is simplified and the problems in the production costs and theproduction yield are overcome.

In addition, when all of the HIL, the HTL and the EML include theorganic compound in Formula 3, which has an excellent hole transportingproperty, the hole injection or transporting barrier is reduced suchthat the emission efficiency is further improved. Namely, since the holeinjection or transporting barrier is reduced, the combination of theholes and the electrons is generated at a center region of the EML suchthat the emission efficiency is improved.

In Formula 3, X is selected from carbon, nitrogen, oxygen and sulfur,and Y is selected from aryl and arylamine. For example, Y may beselected from phenyl, naphthyl, terphenyl, xylene, triphenlyamine,diphenylamine and phenanthrenylamine.

In Formula 2, Y is selected from the followings.

For example, the organic compound in Formula 3 includes the followingcompounds AN-1 to AN-16.

Synthesis Example

A synthesis example of the organic compound is explained.

1. Synthesis of the Compound AN-1 (1) synthesis of3-(10-phenylanthracen-9-yl)-9H-carbazole

3-bromocarbazole (2.54 g, 10.320 mmol), 9-phenyl-boronic acid (3.69 g,12.384 mmol), Na₂CO₃ (2.2 g, 20.64 mmol), Pd(PPh₃)₄ (1.19 g, 1.032 mmol)were put in a 250 mL two-neck flask and dissolved intoluene/ethanol/H₂O. The solution was refluxed and stirred at 120° C.for 12 hours. After completion of the reaction, the solution wasextracted with methylenechloride/H₂O and distilled under reducedpressure to remove the solvent. The resultant was columned with asolution of n-hexane and methylenechloride (4:1) and was re-crystallizedin a solution of methylene chloride and petroleum ether such that thewhite solid compound was obtained, (2.60 g, yield: 60%).

(2) Synthesis of the Compound AN-1

3-(10-phenylanthracen-9-yl)-9H-carbazole (1.68 g, 4.00 mmol),4-bromo-triphenylamine (1.43 g, 4.401 mmol), Pd₂(dba)₃ (110 mg, 0.120mmol), tris-t-butylphosphine (47 μl, 0.200 mmol), sodium tert-butoxide(770 mg, 8.00 mmol) were put in a 250 mL two-neck flask and dissolved intoluene. The solution was refluxed and stirred for 12 hours. Aftercompletion of the reaction, the solution was distilled under reducedpressure to remove the solvent. The resultant was columned with asolution of n-hexane and methylenechloride (4:1) and was re-crystallizedin a solution of methylene chloride and petroleum ether such that thewhite solid compound AN-1 was obtained, (2.53 g, yield: 95%).

2. Synthesis of the Compound AN-2

3-(10-phenylanthracen-9-yl)-9H-carbazole (1.59 g, 3.80 mmol),N-(4-bromophenyl)-N-phenyl-naphthalen-1-amine (1.56 g, 4.17 mmol),Pd₂(dba)₃ (69 mg, 0.076 mmol), tris-t-butylphosphine (27 μl, 0.114mmol), sodium tert-butoxide (728 mg, 7.58 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene. The solution was refluxed andstirred for 12 hours. After completion of the reaction, the solution wasdistilled under reduced pressure to remove the solvent. The resultantwas columned with a solution of n-hexane and methylenechloride (3:1) andwas re-crystallized in a solution of methylene chloride and petroleumether such that the greenish solid compound AN-2 was obtained, (1.64 g,yield: 61%).

3. Synthesis of the Compound AN-3 (1) synthesis ofN-phenylphenanthren-9-amine

9-bromophenanthrene (7.00 g, 27.22 mmol), aniline (3.7 mL, 40.84 mmol),Pd₂(dba)₃ (499 mg, 0.544 mmol), tris-t-butylphosphine (0.123 mL, 0.544mmol), sodium tert-butoxide (3.90 mg, 40.84 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene. The solution was refluxed andstirred for 12 hours. After completion of the reaction, the solution wasextracted with DI water/methylenechloride and distilled under reducedpressure to remove the solvent. The resultant was columned with asolution of n-hexane and methylenechloride (3:1) and was re-crystallizedin a solution of methylene chloride and petroleum ether such that thesolid compound was obtained, (4.60 g, yield: 63%).

(2) synthesis of N-(3-bromophenyl)-N-phenylphenanthren-9-amine

N-phenylphenanthren-9-amine (4.51 g, 16.74 mmol), 1,3-dibromobenzene(6.05 mL, 50.23 mmol), Pd₂(dba)₃ (307 mg, 0.355 mmol),tris-o-tolyphosphine (0.255 mL, 0.837 mmol), sodium tert-butoxide (3.2g, 33.49 mmol) were put in a 250 mL two-neck flask and dissolved intoluene. The solution was refluxed and stirred for 12 hours. Aftercompletion of the reaction, the solution was extracted with DIwater/methylenechloride and distilled under reduced pressure to removethe solvent. The resultant was columned with a solution of n-hexane andmethylenechloride (7:1). The resultant was distilled under reducedpressure and re-crystallized such that the wax compound was obtained,(2.9 g, yield: 41%).

(3) Synthesis of the Compound AN-3

3-(10-phenylanthracen-9-yl)-9H-carbazole (1.25 g, 2.98 mmol),N-(3-bromophenyl)-N-phenylphenanthren-9-amine (1.39 g, 3.28 mmol),Pd₂(dba)₃ (55 mg, 0.060 mmol), tris-t-butylphosphine (0.014 mL, 0.060mmol), sodium tert-butoxide (572 mg, 5.96 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene. The solution was refluxed andstirred for 12 hours. After completion of the reaction, the solution wasextracted with DI water/methylenechloride and distilled under reducedpressure to remove the solvent. The resultant was columned with asolution of n-hexane and methylenechloride (3:1) and was re-crystallizedin a solution of methylene chloride and petroleum ether such that thesolid compound AN-3 was obtained, (1.14 g, yield: 50%).

4. Synthesis of the Compound AN-4 (1) synthesis of6-(10-phenylanthracen-9-yl)-9H-pyrido[2,3-b]indole

bromo-carboline (3.0 g, 12.14 mmol), 9-phenyl-boronic acid (3.98 g,13.36 mmol), Na₂CO₃ (2.57 g, 24.28 mmol), Pd(PPh₃)₄ (1.40 g, 1.21 mmol)were put in a 250 mL two-neck flask and dissolved intoluene/ethanol/H₂O. The solution was refluxed and stirred at 120° C.for 12 hours. After completion of the reaction, the solution wasextracted with methylenechloride/H₂O and distilled under reducedpressure to remove the solvent. The resultant was columned with asolution of n-hexane and ethylacetate (3:1) and was re-crystallized in asolution of methylene chloride and petroleum ether such that the solidcompound was obtained, (2.32 g, yield: 45%).

(2) synthesis of9-(4-iodophenyl)-6-(10-phenylanthracen-9-yl)-9H-pyrido[2,3-b]indole

6-(10-phenylanthracen-9-yl)-9H-pyrido[2,3-b]indole (1.76 g, 4.19 mmol),1,4-diiodobenzene (2.76 g, 8.37 mmol), CuI (319 mg, 1.67 mmol), K₃PO₄(1.78 g, 8.37 mmol), trans-1,2-dicyclohexanediamine (0.2 mL, 1.67 mmol)were put in a 250 mL two-neck flask and dissolved in 1,4-dioxane. Thesolution was refluxed and stirred at 120° C. for 12 hours. Aftercompletion of the reaction, the solution was extracted withmethylenechloride/H₂O and distilled under reduced pressure to remove thesolvent. The resultant was columned with a solution of n-hexane andmethylenechloride (1:5) and was re-crystallized in a solution ofmethylene chloride and petroleum ether such that the solid compound wasobtained, (1.67 g, yield: 64%).

(3) Synthesis of the Compound AN-4

6-(10-phenylanthracen-9-yl)-9H-pyrido[2,3-b]indole (1.58 g, 2.54 mmol),diphenylamine (430 mg, 2.54 mmol), Pd₂(dba)₃ (46 mg, 0.050 mmol),tris-t-butylphosphine (0.012 mL, 0.050 mmol), sodium tert-butoxide (488mg, 5.08 mmol) were put in a 250 mL two-neck flask and dissolved intoluene. The solution was refluxed and stirred at 120° C. for 12 hours.After completion of the reaction, the solution was extracted withmethylenechloride/H₂O and distilled under reduced pressure to remove thesolvent. The resultant was columned with a solution of n-hexane andmethylenechloride (1:5) and was re-crystallized in a solution ofmethylene chloride and petroleum ether such that the solid compound AN-4was obtained, (0.54 g, yield: 32%).

5. Synthesis of the Compound AN-6

3-(10-phenylanthracen-9-yl)-9H-carbazole (1.59 g, 3.80 mmol),N-(3-bromophenyl)-N-phenyl-naphthalen-1-amine (1.56 g, 4.17 mmol),Pd2(dba)3 (69 mg, 0.076 mmol), tris-t-butylphosphine (27 μl, 0.114mmol), sodium tert-butoxide (728 mg, 7.58 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene. The solution was refluxed andstirred for 12 hours. After completion of the reaction, the solution wasdistilled under reduced pressure to remove the solvent. The resultantwas columned with a solution of hexane and ethylacetate (3:1). Thesolution was distilled under reduced pressure and was re-crystallized ina solution of methylene chloride and petroleum ether such that thecompound AN-6 of greenish solid was obtained, (1.64 g, yield: 61%).

6. Synthesis of the Compound AN-8 (1) Synthesis of9-(3-iodophenyl)-6-(10-phenylanthracen-9-yl)-9H-pyrido[2,3-b]indole

6-(10-phenylanthracen-9-yl)-9H-pyrido[2,3-b]indole (1.76 g, 4.19 mmol),1,3-diiodobenzene (2.76 g, 8.37 mmol), CuI (319 mg, 1.67 mmol), K3PO4(1.78 g, 8.37 mmol), trans-1,2-dicyclohexanediamine (0.2 mL, 1.67 mmol)were put in a 250 mL two-neck flask and dissolved in 1,4-dioxane. Thesolution was refluxed and stirred at 120° C. for 12 hours. Aftercompletion of the reaction, the solution was extracted withmethylenechloride and H₂O and was distilled under reduced pressure toremove the solvent. The resultant was columned with a solution of hexaneand methylenechloride (1:5). The solution was re-crystallized in asolution of methylene chloride and petroleum ether such that the whitesolid compound was obtained, (1.66 g, yield: 63%).

(2) Synthesis of the Compound AN-8

9-(3-iodophenyl)-6-(10-phenylanthracen-9-yl)-9H-pyrido[2,3-b]indole(1.58 g, 2.54 mmol), diphenylamine (430 mg, 2.54 mmol), Pd2(dba)3 (46mg, 0.050 mmol), tris-t-butylphosphine (0.012 mL, 0.050 mmol), sodiumtert-butoxide (488 mg, 5.08 mmol) were put in a 250 mL two-neck flaskand dissolved in toluene. The solution was refluxed and stirred at 120°C. for 12 hours. After completion of the reaction, the solution wasextracted with H₂O and was distilled under reduced pressure to removethe solvent. The resultant was columned with a solution of hexane andmethylenechloride (1:5). The solution was distilled under reducedpressure and was re-crystallized in a solution of methylene chloride andpetroleum ether such that the compound AN-8 of solid was obtained, (0.53g, yield: 31%).

7. Synthesis of the Compound AN-11 (1) synthesis ofdiphenanthren-9-ylamine

9-bromophenanthrene (7.00 g, 27.22 mmol), phenanthren-9-amine (5.26 g,27.22 mmol), Pd2(dba)3 (499 mg, 0.544 mmol), tris-t-butylphosphine(0.123 mL, 0.544 mmol), sodium tert-butoxide (3.90 mg, 40.84 mmol) wereput in a 250 mL two-neck flask and dissolved in toluene. The solutionwas refluxed and stirred for 12 hours. After completion of the reaction,the solution was extracted with DI water/methylenechloride and distilledunder reduced pressure to remove the solvent. The resultant was columnedwith a solution of n-hexane and methylenechloride (3:1) and wasre-crystallized in a solution of methylene chloride and petroleum ethersuch that the solid compound was obtained, (4.50 g, yield: 45%).

(2) synthesis ofN-(4-bromophenyl)-N-(phenanthren-9-yl)phenanthren-9-amine

Diphenanthren-9-ylamine (4.50 g, 12.18 mmol), 1,4-dibromobenzene (3.02mL, 25.12 mmol), Pd2(dba)3 (307 mg, 0.355 mmol), tris-o-tolyphosphine(0.255 mL, 0.837 mmol), sodium tert-butoxide (3.2 g, 33.49 mmol) wereput in a 250 mL two-neck flask and dissolved in toluene. The solutionwas refluxed and stirred for 12 hours. After completion of the reaction,the solution was extracted with DI water/methylenechloride and distilledunder reduced pressure to remove the solvent. The resultant was columnedwith a solution of n-hexane and methylenechloride (7:1). The resultantwas distilled under reduced pressure and re-crystallized such that thewax compound was obtained, (2.8 g, yield: 44%).

(3) Synthesis of the Compound AN-11

3-(10-phenylanthracen-9-yl)-9H-carbazole (1.25 g, 2.98 mmol),N-(4-bromophenyl)-N-phenylphenanthren-9-amine (1.56 g, 2.98 mmol),Pd2(dba)3 (55 mg, 0.060 mmol), tris-t-butylphosphine (0.014 mL, 0.060mmol), sodium tert-butoxide (572 mg, 5.96 mmol) were put in a 250 mLtwo-neck flask and dissolved in toluene. The solution was refluxed andstirred for 12 hours. After completion of the reaction, the solution wasextracted with DI water/methylenechloride and distilled under reducedpressure to remove the solvent. The resultant was columned with asolution of n-hexane and methylenechloride (5:1). The solution wasdistilled under reduced pressure and was re-crystallized in a solutionof methylene chloride and petroleum ether such that the solid compoundAN-11 was obtained, (1.14 g, yield: 44%).

The properties of the compounds AN-1 to AN-4, AN-6, AN-8 and AN-11 and ahost compound (Host (ref.)) in Formula 4 were tested and listed in Table3.

TABLE 3 λ_(abs) ^(a) λ_(PL) ^(b) Band gap LUMO ^(d) HOMO ^(e) Compounds(nm) (nm) Energy ^(c) (eV) (eV) Host (ref.) 417 421 3.00 −2.50 −5.50AN-1 419 434 2.96 −2.30 −5.26 AN-2 422 451 2.94 −2.21 −5.15 AN-3 419 4312.96 −2.55 −5.51 AN-4 418 436 2.97 −2.30 −5.27 AN-6 419 451 2.96 −2.23−5.19 AN-8 415 436 2.99 −2.28 −5.27 AN-11 419 431 2.96 −2.63 −5.59^(a)Absorption onset of 0.02 mM solutions in CH₂Cl₂. ^(b)PL maxima of2-methyl THF solutions upon excitation at UV maximum absorption. ^(c)Estimated from the absorption onset. ^(d) LUMO = −[Band gap energy −HOMO level] ^(e) Estimated from the Cyclic Voltammetry instrument.

Example 3 Diode Structure

An indium-tin-oxide (ITO) layer is patterned on a substrate and washedsuch that an emission area of the ITO layer is to be 3 mm*3 mm. Thesubstrate is washed by the UV ozone and is loaded in an evaporationsystem. The substrate is loaded in a vacuum chamber, and the processpressure is adjusted to 1*10⁻⁶˜1*10⁻⁷ torr. On the ITO layer, i) HIL (50Å, host material/HAT-CN (10%)), ii) HTL (300 Å, host material), iii) EML(700 Å, host material/dopant material (15%)), iv) ETL (200 Å, Alq3), v)EIL (10 Å, LiF), and vi) cathode (1000 Å, Al) are sequentiallydeposited. The UV curable epoxy and the getter are used forencapsulation such that the diode is obtained. The dopant material forthe EML isN,N′-bis(2,4-diphenyl)-N,N′-bis(2-fluorophenyl)-pyrene-1,6-diamine.

1. Comparative Example Diode (Ref.)

The compound in Formula 4 is used the host material of the EIL, the ETLand the EML.

2. AN-1 Diode

The compound AN-1 is used the host material of the EIL, the ETL and theEML.

3. AN-3 Diode

The compound AN-3 is used the host material of the EIL, the ETL and theEML.

4. AN-6 Diode

The compound AN-6 is used the host material of the EIL, the ETL and theEML.

5. AN-8 Diode

The compound AN-8 is used the host material of the EIL, the ETL and theEML.

6. AN-11 Diode

The compound AN-11 is used the host material of the EIL, the ETL and theEML.

The above diodes are fabricated with the same conditions except the hostmaterial of the EIL, the ETL and the EML. The properties of the diodeswere tested and listed in Table 4.

TABLE 4 @10 mA/cm² Host Volt(V) Cd/A Im/W EQE (%) cd/m²(max) CIE x CIE yRef. 3.19 1.01 0.99 1.17 100 0.144 0.098 AN-1 2.98 4.30 4.53 4.46 4530.147 0.116 AN-3 2.99 4.12 4.33 4.53 433 0.143 0.107 AN-6 3.00 4.04 4.233.61 423 0.145 0.144 AN-8 3.10 1.91 1.93 2.42 193 0.144 0.087 AN-11 3.123.91 3.94 4.15 394 0.147 0.111

Referring to Table 4, in comparison to the Comparative Example (Ref.),the diode including the organic compounds AN-1, AN-3, AN-6, AN-8 andAN-11 of the embodiment of the invention has advantages in the drivingvoltage, the emission efficiency, and so on. Since the organic compoundhas an excellent hole injection and/or transporting property, thecombination of the holes and the electrons is generated at a centerregion of the EML such that the emission efficiency is improved.

Namely, referring to Table 3, the organic compounds of the embodiment ofthe invention and the reference host have similar properties, e.g., LUMOand HOMO. However, the reference host has a strong electron propertysuch that the hole injection and/or transportation is restricted by thereference host. On the other hand, since the organic compound of theembodiment of the invention has a strong hole property, the holeinjection and/or transportation becomes easier. As a result, in the OLEDincluding the organic compound of the embodiment of the invention, thecombination of the holes and the electrons is generated at a centerregion of the EML such that the emission efficiency is improved.

In addition, since the organic compounds of the embodiment of theinvention can be used for all of the HIL, the HTL and the EML, thestructure and the fabricating process of the OLED are simplified.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the embodiment of theinvention without departing from the spirit or scope of the invention.Thus, it is intended that the embodiment of the invention cover themodifications and variations of this invention provided they come withinthe scope of the appended claims and their equivalents.

What is claimed is:
 1. An organic electroluminescent device, comprising:a first electrode; a second electrode facing the first electrode; afirst charge carrying layer disposed between the first electrode and thesecond electrode, the first charge carrying layer being disposedadjacent to the first electrode; and a second charge carrying layerdisposed between the first electrode and the second electrode, thesecond charge carrying layer disposed adjacent to the second electrode,wherein the first charge carrying layer includes an emitting sub-layer,a hole injection sub-layer and a hole transporting sub-layer between thehole injection sub-layer and the emitting sub-layer, wherein the holeinjection sub-layer includes an organic compound of Formula:

wherein X is selected from carbon and nitrogen, and Y is selected fromaryl and arylamine, and wherein the hole injection sub-layer furtherincludes an organic material of Formula:


2. The organic electroluminescent device according to claim 1, whereinthe Y is selected from phenyl, naphthyl, terphenyl, xylene,triphenlyamine, diphenylamine and phenanthrenylamine.
 3. The organicelectroluminescent device according to claim 1, wherein the organiccompound of the Formula is selected from the followings:


4. The organic electroluminescent device according to claim 1, whereinthe hole transporting sub-layer includes the organic compound of theFormula.
 5. The organic electroluminescent device according to claim 1,wherein the emitting sub-layer includes the organic compound as a hostmaterial and a dopant material doped to the host material.
 6. Theorganic electroluminescent device according to claim 1, wherein theorganic material of the Formula has 0.1 to 20 weight % with respect to atotal weight of the hole injection sub-layer.